Diabetes is the most common cause of end stage renal disease (ESRD) in the United States, accounting for ˜40% of the cases of renal failure at the time of initiation of dialysis or transplantation. Diabetic nephropathy (DN) is a kidney disease that can occur as a result of diabetes and is a leading cause of kidney failure and ESRD. Increased demand upon the kidneys is indicated by an above-normal glomerular filtration rate (GFR). High glucose levels are believed to cause damage to the glomeruous where blood enters the kidney. For patients suffering from DN, the delicate filtering system in the kidney becomes damaged, initially becoming leaky to large blood proteins such as albumin which are then lost in urine.
Typically, DN is prevented or controlled by controlling the blood glucose level. This has been used to prevent the development and slow the progression of diabetic nephropathy, as well as the other complications of diabetes. DN begins with a tiny amount of protein appearing in the urine—this is called microalbuminuria. Over about 10-15 years proteinuria can increase, and nephrotic syndrome may develop. The development of proteinuria reduces the kidneys' ability to remove poisons from the blood such that 5-10 years later the kidneys are almost completely unable to remove these poisons from the blood. This is called “end-stage renal disease” (ESRD), and, unless treated, can be fatal.
An abnormal condition that can develop or worsen in DN patients is high blood pressure. This can be the first symptom (abnormality) to develop. Diabetic nephropathy is also an indication of worsening blood vessel disease throughout the body. Diabetic eye disease is usually present by this stage indicating damage to smaller blood vessels. Larger blood vessels (arteries) are almost always affected. This can lead to heart attacks, strokes, and circulatory disease occurring more often and at a younger age than usual. Commonly diabetes will have also resulted in damage to small nerves causing “diabetic peripheral nephropathy” and “autonomic neuropathy”. Thus, Diabetic nephropathy (DN) is associated with markedly higher morbidity and mortality rates.
Current methods for treating DN include managing blood pressure. This usually requires more than one type of blood pressure medicine to achieve. Two classes of drug used to control blood pressure deserve special mention. These are the Angiotensin-Converting Enzyme (ACE) inhibitors and angiotensin II (AT II) receptor antagonists. Many studies have documented the greater potency of ACE inhibitors at reducing proteinuria and the progression of kidney disease compared to other classes of drug. These drugs not only reduce blood pressure in the large blood vessels, but also directly in the kidneys' filtering system (called glomeruli). Although these drugs tend to be preferentially used, they need to be monitored as they may have a detrimental effect on some people. It is thought that AT II receptor antagonists will have a similar effect, and these are often used in those unable to tolerate ACE inhibitors.
Accordingly, there is a need for the development of additional methods and suitable pharmaceutical agents useful in therapy for treatment and/or prevention of diabetic kidney disease particularly diabetic nephropathy. There is currently a need for a method to treat renal injury associated with diabetic kidney disease, such as, for example, diabetic nephropathy and renal injury associated with diabetic nephropathy.